My foray into "accident invetigating"

[jbird]

I decided to reproduce as best I could, Thurday's crash landing of a 737 in Chicago. The plane, overran the runway and went into the highway at 46 mph. There was a tail wind and icing on runway 13. I used a 20 knt tailwind, blinding snow and severe icing in FS2004. The results: the tailwind carried me 25% past the touchdown area, and even as the plane went into that 46 mph zone, it accelerated up to 52 with the autopilot off and hit that roadway. I think we can pretty much determine wind shear effects and severe icing, combined with pilot intent on landing in less than ideal as the cause of the accident. The length of the runway in my opinion is barely acceptable, and scary to see on appr. The pilots did handle things much better than I.

[Tom_M]

Interesting... Let's see what the official report says

[Nexus]

I think we can pretty much determine wind shear effects and severe icing

How do you know the crashed was caused by windshear? And if they had 20kt tailwind, why didnt they simply choose RWY31?

There were aircrafts landing earlier than the WN flight, and they managed to stop safely. I wonder if it has something to do with WN not using autobrakes

[Mobius]

I don't think wind shear or icing would affect the stopping distance of the aircraft.  And ATC wouldn't land an aircraft with a 20 kt tailwind in any condition, unless they were not able to make any other landing, which it didn't sound like was the case here.  I went flying yesterday, (Friday, the day after the accident), and I live about two hours north of Chicago so we had similar conditions the night before, but even yesterday afternoon when I was landing, I hopped on the brakes once I touched down to make the first taxiway turnoff (I wouldn't normally, but it was a BFR and the CFI told me to do it ) and I skidded down probably 100-150 ft of the runway because it was covered in packed snow and ice.  I did that in a C172, so I can imagine that a loaded 737 would slide substantially farther than a lightly loaded 172 if the brakes were being applied.

Does a 737 have ABS, that might have helped....

[Skligmund]

Yes, 737's have Anti-lock Braking Systems.


I don;t know all the cicumstances, so I won't think I know what happened.

[Mobius]

Oh, I see.  Well, I have to agree, the only information most of us can get on it is from the news, and they rarely know anything, so I don't think anyone can make a guess as to why it happened just yet.

[BAW0343]

i sont know where you got the 20 kts tailwind. if that is the landing conditions of the accdent then it is ATC/Pilot error  ATC for landing him in wrong direction and pilot for umm something i think   maby i'm wrong. We will find out soon tho (i hope)

[Skligmund]

If it was as you think, the NTSB would write (only about pilot):

Probable Cause:

Failure to initiate go-around - Pilot in command

[JBaymore]

I'm with Nexus on the trail of something to do with autobrakes (or reversers).

best,

.................john

[wilderobb]

Every time I crash it's because I did something stupid. ie. forcing a landing, Landing when and where I should'nt, forgetting something ect. I don't do those things any more.

[BFMF]

A 20knot tail wind??? I don't think so......

When I was flying yesterday, I landed on a runway with packed snow and ice. I knew not to hit the brakes hard, but I did tap them. I then let the aircraft coast to a stop

[Nexus]

A 20knot tail wind??? I don't think so......

When I was flying yesterday, I landed on a runway with packed snow and ice. I knew not to hit the brakes hard, but I did tap them. I then let the aircraft coast to a stop

Yeah but think about the inertia difference between a small GA airplane and a Boeing 737. Once that 737 starts skidding, it's going to take a whole lotta runway to make it stop. The braking system on the 737 does indeed have anti-skid protection aswell as hydroplane protection when braking manually, but the systems cant defy the laws of physics.

[BFMF]

Yeah but think about the inertia difference between a small GA airplane and a Boeing 737.

Mobious mentioned his flying experience with icy runways, so I thought I was share my(but limited) experience

[jbird]

Yeah Im currently onto the thrust reverser problem with you. I noticed it didnt look like deployment in any of the photos earlier, but for some reason it wasnt clicking with me. Guess I was a bonehead there. Now the news is reporting the same reverser idea. As for the 20 knots on that tail wind, I could only guess based on the fact there was a tailwind at the time in a what the media has categorized as a "heavy" storm. I cant be sure as we only got just over 2" in Rochester, NY-a real non event I know that I had a feeling of being carried past touchdown in sim, and as I hit the reported 46 kt mark, that plane did accelerate into a street.

[expat]

No quite sure what we are calling a "thrust reverser problem", however here are a couple of points about reversers.
1. The aircraft can land and stop without the use of thrust reversers. If this was not the case then you would not be able, in accordance with the MEL (minimal equipment list) to INOP them (as I have, many times)
2. Thrust reversers are an augment to braking. There primary use is to reduce the wear and tear on the braking system.
3. Below about 90knots, they become very ineffective. You also run the risk of ingestion at lower speeds.
4. Yes, but in FS2004 I use them...............If you use them any place other than the runway, you will not receive any further invitations to visit said airport.
5. Well, in FS2004............ See speed point in point 3.

Also as to photos showing no deployed reversers, the crews still have shutdown procedures, even in the event of an accident. On the 737, raising the thrust reverser levers will only open the reverser doors, you have to  raise the levers further  to enable thrust to be produced to be then, reversed.   It would be a very unnatural movement for the pilot to shut down the engines with the reversers levers in the raise position, thus leaving the reversers deployed.
Not to mention dangerous later when the aircraft is removed. Applying hydraulic power would, without warning, will close them.

Matt